Well-formedness check for assume and assert instructions

Check that the guard evaluates to a Boolean value.

src/goto-programs/goto_program.cpp

@@ -685,8 +685,18 @@ void goto_programt::instructiont::validate(
   case GOTO:
     break;
   case ASSUME:
+    DATA_CHECK_WITH_DIAGNOSTICS(
+      vm,
+      targets.empty(),
+      "assume instruction should not have a target",
+      source_location);
     break;
   case ASSERT:
+    DATA_CHECK_WITH_DIAGNOSTICS(
+      vm,
+      targets.empty(),
+      "assert instruction should not have a target",
+      source_location);
     break;
   case OTHER:
     break;

src/util/std_code.h

@@ -538,6 +538,11 @@ inline code_assumet &to_code_assume(codet &code)
   return static_cast<code_assumet &>(code);
 }
 
+inline void validate_expr(const code_assumet &x)
+{
+  validate_operands(x, 1, "assume must have one operand");
+}
+
 /// A non-fatal assertion, which checks a condition then permits execution to
 /// continue.
 class code_assertt:public codet
@@ -585,6 +590,11 @@ inline code_assertt &to_code_assert(codet &code)
   return static_cast<code_assertt &>(code);
 }
 
+inline void validate_expr(const code_assertt &x)
+{
+  validate_operands(x, 1, "assert must have one operand");
+}
+
 /// Create a fatal assertion, which checks a condition and then halts if it does
 /// not hold. Equivalent to `ASSERT(condition); ASSUME(condition)`.
 ///

unit/Makefile

@@ -15,6 +15,7 @@ SRC += analyses/ai/ai.cpp \
        analyses/does_remove_const/does_type_preserve_const_correctness.cpp \
        analyses/does_remove_const/is_type_at_least_as_const_as.cpp \
        compound_block_locations.cpp \
+       goto-programs/goto_program_assume.cpp \
        goto-programs/goto_program_dead.cpp \
        goto-programs/goto_program_declaration.cpp \
        goto-programs/goto_trace_output.cpp \

unit/goto-programs/goto_program_assume.cpp

@@ -0,0 +1,64 @@
+/*******************************************************************\
+
+  Module: Unit tests for goto_program::validate
+
+  Author: Diffblue Ltd.
+
+ \*******************************************************************/
+
+#include <goto-programs/goto_function.h>
+#include <testing-utils/catch.hpp>
+#include <util/arith_tools.h>
+
+SCENARIO(
+  "Validation of well-formed assert/assume codes",
+  "[core][goto-programs][validate]")
+{
+  GIVEN("A program with one assumption")
+  {
+    symbol_tablet symbol_table;
+    const typet type1 = signedbv_typet(32);
+    symbolt symbol;
+    irep_idt symbol_name = "a";
+    symbol.name = symbol_name;
+    symbol_exprt varx(symbol_name, type1);
+    exprt val10 = from_integer(10, type1);
+    binary_relation_exprt x_le_10(varx, ID_le, val10);
+
+    goto_functiont goto_function;
+    auto &instructions = goto_function.body.instructions;
+    instructions.emplace_back(goto_program_instruction_typet::ASSUME);
+
+    symbol.type = type1;
+    symbol_table.insert(symbol);
+    namespacet ns(symbol_table);
+    instructions.back().make_assertion(x_le_10);
+
+    WHEN("Instruction has no targets")
+    {
+      THEN("The consistency check succeeds")
+      {
+        goto_function.body.validate(ns, validation_modet::INVARIANT);
+        REQUIRE(true);
+      }
+    }
+
+    WHEN("Instruction has a target")
+    {
+      instructions.back().targets.push_back(instructions.begin());
+      THEN("The consistency check fails")
+      {
+        bool caught = false;
+        try
+        {
+          goto_function.body.validate(ns, validation_modet::EXCEPTION);
+        }
+        catch(incorrect_goto_program_exceptiont &e)
+        {
+          caught = true;
+        }
+        REQUIRE(caught);
+      }
+    }
+  }
+}